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| United States Patent |
5,650,548
|
|
Theriot
, et al.
|
July 22, 1997
|
Olefin oligomerization process
Abstract
Alpha-olefin oligomer is prepared by contacting an alpha-olefin monomer
which contains from about 6 to about 20 carbon atoms with a catalyst
system comprising boron trifluoride, a protic promoter, and an organic
sulfone, sulfoxide, carbonate, thiocarbonate, or sulfonate. Oligomer
containing as much as 50% or more of dimer can be produced at high
conversions, at modest reaction temperatures, and in acceptably short
reaction periods.
| Inventors:
|
Theriot; Kevin J. (Baton Rouge, LA);
Irwin; Robert G. (Prairieville, LA)
|
| Assignee:
|
Amoco Corporation (Chicago, IL)
|
| Appl. No.:
|
491459 |
| Filed:
|
June 16, 1995 |
| Current U.S. Class: |
585/525; 585/500; 585/510; 585/515; 585/520; 585/526; 585/529 |
| Intern'l Class: |
C07C 002/08 |
| Field of Search: |
585/500,510,515,520,525,526,529
|
References Cited
U.S. Patent Documents
| 2500161 | Mar., 1950 | Seger et al.
| |
| 2500163 | Mar., 1950 | Garwood.
| |
| 2766312 | Oct., 1956 | Serniuk.
| |
| 2806072 | Sep., 1957 | Cohen et al.
| |
| 3382291 | May., 1968 | Brennan.
| |
| 3769363 | Oct., 1973 | Brennan.
| |
| 3997621 | Dec., 1976 | Brennan.
| |
| 4024203 | May., 1977 | Torck et al. | 585/514.
|
| 4172855 | Oct., 1979 | Shubkin et al. | 585/16.
|
| 4218330 | Aug., 1980 | Shubkin | 252/46.
|
| 4409415 | Oct., 1983 | Morganson et al. | 585/525.
|
| 4436947 | Mar., 1984 | Morganson et al. | 585/525.
|
| 4902846 | Feb., 1990 | DiLeo et al. | 585/525.
|
| 4935570 | Jun., 1990 | Nelson et al. | 585/329.
|
| 4950822 | Aug., 1990 | Dileo et al. | 585/310.
|
| 4956512 | Sep., 1990 | Nissfolk et al. | 585/521.
|
| 4973789 | Nov., 1990 | Karn et al. | 585/525.
|
| 4982026 | Jan., 1991 | Karn et al. | 585/18.
|
| 5068487 | Nov., 1991 | Theriot | 585/510.
|
| 5191140 | Mar., 1993 | Akatsu et al. | 585/525.
|
| 5225588 | Jul., 1993 | Senaratne et al. | 560/71.
|
| 5241085 | Aug., 1993 | Senaratne et al. | 549/396.
|
| 5250750 | Oct., 1993 | Shubkin et al. | 174/17.
|
| 5396013 | Mar., 1995 | Theriot | 585/510.
|
| 5420373 | May., 1995 | Hope et al. | 585/525.
|
Primary Examiner: Caldarola; Glenn A.
Assistant Examiner: Wood; Elizabeth D.
Attorney, Agent or Firm: DiSalvo; Joseph, Hensley; Stephen L.
Claims
We claim:
1. A process of preparing alpha-olefin oligomer which comprises contacting
an oligomerizable olefin monomer with a catalyst system comprising a
catalytic amount of boron trifluoride, an oligomerization promoting amount
of a protic promoter, and an organic modifier selected from the group
consisting of sulfoxide, carbonate, and sulfonate at a pressure from about
atmospheric to about 1000 psig, a temperature of about 0.degree. C. to
about 200.degree. C., and a molar ratio in the range of about 0.1 moles to
about 10 moles of modifier per mole of promoter wherein the olefin monomer
is a C.sub.6 to C.sub.20 linear olefin comprising at least 50 mole % alpha
olefin.
2. The process according to claim 1 wherein the protic promoter is selected
from the group consisting of water, at least one alcohol, and mixtures
thereof.
3. A process according to claim 1 wherein the protic promoter is an
alcohol.
4. A process according to claim 1 wherein the olefin monomer has from 8 to
14 carbon atoms.
5. A process according to claim 1 wherein the olefin monomer is 1-decene.
6. A process according to claim 1 wherein the modifier is a hydrocarbyl
sulfoxide.
7. A process according to claim 1 wherein the modifier is a hydrocarbyl
carbonate.
8. A process according to claim 1 wherein the modifier is a hydrocarbyl
sulfonate.
9. A process according to claim 1 wherein the temperature is maintained in
the range of about 20.degree. to about 60.degree. C. and wherein the
pressure is maintained in the range of about 5 to about 100 psig.
10. A process according to claim 1 wherein the modifier is selected from
the group consisting of dimethylsulfoxide and propylene carbonate.
11. A process of preparing alpha-olefin oligomer which comprises contacting
an oligomerizable olefin monomer wherein the olefin monomer is C.sub.8 to
C.sub.14 linear olefin comprising at least 50 mole % alpha olefin with a
catalytic amount of boron trifluoride, a protic promoter, and a modifier
selected from the group consisting of organic sulfoxides, organic
carbonates, and organic sulfonates, at a temperature in the range of about
30.degree. to about 150.degree. C., under an atmosphere comprising boron
trifluoride at a pressure in the range of 5 psig to about 100 psig, and in
proportions in the range of about 0.5 to about 2 moles of modifier per
mole of promoter thereby forming an oligomerization product mixture
containing 50 wt. % or more of dimer.
12. A process according to claim 11 wherein the protic promoter is selected
from the group consisting of water, at least one alcohol, and mixtures
thereof.
13. A process according to claim 11 wherein the olefin monomer is 1-decene.
14. A process according to claim 11 wherein the oligomerization is
terminated by quenching the said oligomerization product mixture with
water or an aqueous solution.
15. A process according to claim 11 wherein said proportions are in the
range of about 0.75 to about 1.25 moles of modifier per mole of promoter.
16. A process according to claim 11 wherein the temperature is maintained
in the range of about 20.degree. to about 60.degree. C.
17. A process according to claim 11 wherein the olefin monomer is 1-decene,
and wherein said proportions are in the range of about 0.75 to about 1.25
moles of modifier per mole of promoter.
18. A process according to claim 11 wherein the protic promoter is at least
one alcohol and wherein the modifier is selected from the group consisting
of a hydrocarbyl sulfoxide, a hydrocarbyl carbonate, and a hydrocarbyl
sulfonate.
19. A process according to claim 18 wherein the olefin monomer is 1-decene,
and wherein said promoter and said modifier are employed in equimolar
proportions.
20. A process according to claim 11 wherein the protic promoter is at least
one alcohol, wherein the modifier is selected from the group consisting of
dimethylsulfoxide and propylene carbonate, and wherein the temperature is
maintained in the range of about 40.degree. to about 60.degree. C.
21. A process according to claim 20 wherein said promoter and said modifier
are employed in equimolar proportions.
22. A process according to claim 21 wherein the olefin monomer is 1-decene.
23. A process according to claim 22 wherein the protic promoter is selected
from the group consisting of 1-propanol, 1-butanol, 1-methoxy-2-propanol,
and 2-methoxyethanol.
24. A process according to claim 1 wherein the modifier is an organic
thiocarbonate.
25. A process according to claim 1 wherein the modifier is a hydrocarbyl
thiocarbonate.
26. A process according to claim 2 in which the alcohol is an alcohol
alkoxylate.
27. A process according to claim 3 in which the alcohol is an alcohol
alkoxylate.
28. A process according to claim 12 in which the alcohol is an alcohol
alkoxylate.
29. A process according to claim 18 wherein the modifier is a hydrocarbyl
thiocarbonate.
30. A process according to claim 20 in which the alcohol is an alcohol
alkoxylate.
31. A process of preparing alpha-olefin oligomer which comprises contacting
an oligomerizable olefin monomer with a catalyst system consisting of a
catalytic amount of boron trifluoride, an oligomerization promoting amount
of a protic promoter, and an organic sulfone modifier under an atmosphere
comprising boron trifluoride at a pressure from about atmospheric to about
1000 psig, a temperature of about 0.degree. C. to about 200.degree. C.,
and a molar ratio in the range of about 0.1 mole to about 10 moles of
organic sulfone modifier per mole of promoter wherein the olefin monomer
is a C.sub.6 to C.sub.20 linear olefin comprising at least 50 mole % alpha
olefin.
32. A process according to claim 31 wherein the organic sulfone modifier is
sulfolane.
33. A process of preparing alpha-olefin oligomer which comprises contacting
an oligomerizable olefin monomer, wherein the olefin monomer is C.sub.8 to
C.sub.14 linear olefin comprising at least 50 mole % alpha olefin, with a
catalyst system consisting of a catalytic amount of boron trifluoride, a
protic promoter employed in the range of about 1.0 mole % based on olefin
monomer, and an organic sulfone modifier at a temperature in the range of
about 30.degree. to about 150.degree. C., under an atmosphere comprising
boron trifluoride at a pressure in the range of 5 psig to about 100 psig,
and in proportions in the range of about 0.5 to about 2 moles of organic
sulfone modifier per mole of promoter thereby forming an oligomerization
product mixture containing at least 50 wt. % dimer.
34. A process according to claim 33 wherein the organic sulfone modifier is
a hydrocarbyl monosulfone.
35. A process according to claim 33 wherein the organic sulfone modifier
sulfolane.
Description
TECHNICAL FIELD
This invention relates generally to the preparation of alpha-olefin
oligomers which are useful as synthetic lubricants and functional fluids.
More particularly, this invention relates to BF.sub.3 -promoter catalyst
systems which use a modifier to control the oligomer product distribution
and provide higher percentages of lower oligomers, especially dimers.
BACKGROUND
Alpha-olefin oligomers and their use as synthetic lubricants are
well-known. The oligomers are usually hydrogenated in order to improve
their stability. Early reports of such oligomeric synthetic lubricants
appear in Seger et al. U.S. Pat. Nos. 2,500,161 and Garwood 2,500,163.
Oligomerization of alpha-olefins in a Group IV metal oxide bed using a
BF.sub.3 -protic promoter catalyst is described in U.S. Pat. No.
2,766,312. Promoters referred to therein include water, carboxylic acid,
alkyl halides, alcohols and ethers.
U.S. Pat. No. 2,806,072 discloses the dimerization of C.sub.6 -C.sub.12
polypropylenes using a preformed BF.sub.3 -dialkyl ether catalyst.
Oligomerization of olefins using BF.sub.3 -promoter catalyst complexes of
acid anhydrides, esters, ketones and aldehydes is described in U.S. Pat.
No. 3,382,291.
U.S. Pat. No. 3,769,363 to Brennan discloses oligomerization of C.sub.6
-C.sub.12 normal alpha-olefins, such as 1-decene, with BF.sub.3 and
C.sub.5 carboxylic acid to improve trimer yields.
U.S. Pat. No. 3,997,621 also to Brennan describes oligomerization of
C.sub.6 -C.sub.12 normal alpha-olefins with BF.sub.3 using alcohols or
water promoters in conjunction with small amounts of methyl and ethyl
esters of a C.sub.2 -C.sub.5 monocarboxylic acid to improve trimer yields.
In U.S. Pat. No. 4,172,855 BF.sub.3 -promoter catalysts for grafting a
second alpha-olefin onto a C.sub.6 -C.sub.12 alpha-olefin dimer to form a
low volatility lubricating oil is described. The promoters include glycol
ethers such as ethylene glycol monomethyl ether and propylene glycol
monoethyl ether, and diisobutyl ether.
U.S. Pat. No. 4,218,330 to Shubkin describes dimerization of C.sub.12
-C.sub.18 alpha-olefin monomer with a BF.sub.3 -water complex and an
excess of BF.sub.3. Unreacted monomer is distilled from the reaction
product leaving mainly dimer with minor amounts of trimer and higher
oligomers. The product is hydrogenated for use as a lubricant.
U.S. Pat. No. 4,436,947 to Morganson et al. discloses oligomerization of
C.sub.6 -C.sub.20 olefins, such as 1-decene, with BF.sub.3 and a mixture
of an aliphatic alcohol, an aliphatic ketone, and a polyol. The product is
mainly trimer.
U.S. Pat. No. 4,982,026 to Karn describes polymerization of C.sub.2
-C.sub.6 alkene monomers with BF.sub.3 and a strong acid, such as
phosphoric acid to produce a polymer having a molecular weight of from 250
to 500 and having a high vinylidene content.
U.S. Pat. No. 5,068,487 describes a process for producing products
containing predominately dimers and trimers of alpha-olefins using a
BF.sub.3 catalyst promoted by an alcohol alkoxylate.
U.S. Pat. No. 5,191,140 discloses a process for making alpha-olefin
oligomers by use of BF.sub.3 promoted by at least two of water, alcohols
and anhydrides to peak the reaction at lower molecular weight product.
In U.S. Pat. No. 5,396,013 it is shown that polyethers will moderate
promoted BF.sub.3 -catalyzed oligomerizations to provide either
predominately dimer- or trimer-containing oligomers.
U.S. Pat. No. 5,420,373 discloses a process for producing predominately
dimer and trimer from C.sub.6 -C.sub.20 olefins, such as 1-decene, with
BF.sub.3 and a hydroxy carbonyl promoter--i.e., a hydroxy ketone or a
hydroxy aldehyde. Secondary promoters may also be used, namely aldehydes,
alcohols, alcohol alkoxylates, carboxylic acids, ethers, ketones, and
their mixtures.
The particular application for which the oligomer oils are used depends
largely upon their viscosity, with viscosities of about 2-10 cSt at
100.degree. C. being preferred for general lubricating oil applications.
These materials are, in general, mixtures of different percentages of
dimer, trimer, tetramer, pentamer and, in the case of the higher viscosity
products in this range, higher oligomers as well. To increase viscosity,
processes are used which either produce more of the higher oligomers or
some of the lower oligomers are removed such as by distillation.
Most lower viscosity dimer products are obtained as by-products of the
production of higher viscosity synthetic oils. Because of increasing use
of dimers in applications such as low temperature lubricants and drilling
fluids, methods for their preferential production are of particular
interest. Although higher oligomerization temperatures tend to increase
dimer formation, use of such higher temperatures can cause corrosion of
process equipment.
SUMMARY OF THE INVENTION
New, highly effective modifiers for BF.sub.3 -catalyzed oligomerization
reactions have been discovered. By the practice of preferred embodiments
of this invention it has been found possible to modify the promoted
catalytic reaction so that product containing as much as 50% or more of
dimer can be produced at high conversions, at modest reaction
temperatures, and in acceptably short reaction periods.
The modifiers employed pursuant to this invention are organic sulfones,
sulfoxides, carbonates, thiocarbonates, and sulfonates.
Accordingly, in one of its embodiments this invention provides a process of
preparing alpha-olefin oligomer which comprises contacting an alpha-olefin
monomer which contains from about 6 to about 20 carbon atoms with a
catalyst system comprising boron trifluoride, a protic promoter, and an
organic sulfone, sulfoxide, carbonate, thiocarbonate, or sulfonate.
In a preferred embodiment the foregoing process is conducted under
oligomerization conditions forming a reaction mixture that contains 50 wt.
% or more of dimer, terminating the oligomerization in said reaction
mixture, and recovering the dimer from said reaction mixture, for example,
by distillation. The preferred oligomerization conditions which form 50
wt. % or more dimer are temperatures of about 30.degree. to about
150.degree. C. under an atmosphere comprising boron trifluoride at a
pressure of about 5 to about 100 psig, and in proportions in the range of
about 0.5 to about 2.0 moles of modifier per mole of promoter. It has been
found possible to conduct the process whereby at conversions upwards from
75%, and even above 90%, oligomerization reaction product mixtures
containing less than 5 wt. % of tetramer and higher oligomer are formed,
and this constitutes a particularly preferred embodiment of this
invention. The especially preferred oligomerization conditions which yield
75% and even above 90% conversion and less than 5 wt. % tetramer and
higher oligomer are use of 1-decene as the olefin monomer, temperatures of
about 40.degree. to about 60.degree. C. under an atmosphere comprising
boron trifluoride at a pressure of about 5 to about 100 psig, in
proportions of about 1.0 mole % protic promoter based on olefin monomer,
and in proportions in the range of about 0.75 to about 1.25 moles of
modifier per mole of promoter.
Another preferred embodiment utilizes water and/or at least one alkanol as
the catalyst promoter in the each of the foregoing processes.
Still another preferred embodiment involves conducting a process of this
invention using as the protic promoter an alcohol alkoxylate such as
described in U.S. Pat. No. 5,068,487, such as 1-methoxy-2-propanol and/or
2-methoxyethanol.
A further embodiment of this invention involves use of a modifier of this
invention in the form of an oligomer or polymer of sufficient molecular
weight to enable the modifier to be readily removed from the reaction
product mixture on completion of the oligomerization reaction.
The above and other embodiments and features of this invention will become
still further apparent from the ensuing description and appended claims.
FURTHER DESCRIPTION
The olefins used in making the oligomers are predominately (at least 50
mole %) C.sub.6 -C.sub.20 straight chain (i.e., linear) monoolefinically
unsaturated hydrocarbons in which the olefinic unsaturation exists in the
1- or alpha-position of the straight chain. Such alpha-olefins are
available as articles of commerce, and can be made by thermal cracking of
paraffinic hydrocarbons or by well-known Ziegler ethylene chain growth
technology. Individual olefins can be used as well as mixtures of such
olefins. Examples of olefins that can be used are 1-hexene, 1-heptene,
1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene,
1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, and mixtures of two
or more of such 1-olefins. Remotely branched 1-olefins such as
5-methyl-1-heptene, 6-methyl-1-heptene, 6-methyl-1-octene, 7-methyl
-1-octene, 6,7-dimethyl-1-octene, 7,7-dimethyl-1-octene,
8-methyl-1-nonene, and like 1-olefins can also be used especially when
used together with linear 1-olefins. The more preferred olefins are linear
alpha-olefin monomers containing about 8-14 carbon atoms. The most
preferred 1-olefin monomer is 1-decene.
Minor amounts of up to about 50, and usually less than 25 mole of internal
and/or vinylidene olefins can be present in the olefin monomers.
Oligomerization is effected by contacting the monomer(s) with a catalytic
amount of boron trifluoride, which typically is at least about 0.002 moles
per mole of olefin, together with a protic promoter and a modifier.
Preferably the reaction is performed in a reaction mixture saturated with
boron trifluoride or in a sealed agitated reactor under an atmosphere
enriched in boron trifluoride.
Among the protic promoters that can be used are water, carboxylic acids,
mineral acids, alcohols, phenols, carboxylic acid esters and anhydrides,
ketones, aldehydes, hydroxy ketones, hydroxy aldehydes, alcohol
alkoxylates, and mixtures of any two or more of the foregoing. Preferred
are water, C.sub.1 to C.sub.24 alcohols and, more preferably, C.sub.1 to
C.sub.12 alcohols, and alcohol alkoxylates such as described in U.S. Pat.
No. 5,068,487. Examples of preferred alcohols include methanol, ethanol,
1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 1-pentanol,
2-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol,
2-ethyl-1-hexanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, and
mixtures of two or more C.sub.1 to C.sub.12 alcohols. Of these, 1-propanol
and 1-butanol are particularly preferred. Examples of alcohol alkoxylates
include 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol,
4-ethoxy-1-butanol, 2-butoxyethanol, and their analogs and homologs. The
protic promoter is used in an oligomerization-promoting amount, i.e., an
amount that causes the BF.sub.3 to function as an oligomerization
catalyst, such as for example from about 0.001 to about 0.04 moles per
mole of alpha-olefin monomer(s). In general the BF.sub.3 is used in a
molar excess relative to the quantity of promoter(s) used, typically by
maintaining a pressurized atmosphere of BF.sub.3 or BF.sub.3 and nitrogen
in the reaction vessel. The promoter can be mixed with the olefin feed or
the promoter can be charged separately to the reactor, either entirely at
the outset or portionwise as the oligomerization proceeds.
The organic sulfones, sulfoxides, carbonates, thiocarbonates, and
sulfonates used in the practice of this invention can either contain no
additional functionality in the molecule or they can contain additional
functionality provided the functionality is such that it does not
significantly impair the effectiveness of the modifier. Linkages or
substituents that do not impair the effectiveness of the modifiers and
that thus can be present therein are the following: halide,
hydrocarbyloxy, hydrocarbylthio, ether oxygen linkage, thioether sulfur
linkage, nitro, nitrile, hydrocarbylsilyl, carbonyl, and thiocarbonyl.
A few example of modifiers having additional non-harmful functionality are:
2,4-bis(methylsulfonyl)-1-chlorobenzene; p-chlorophenyl
2-chloro-1,1,2-trifluoroethyl sulfone; 4-chlorophenyl sulfone;
4-chlorophenyl sulfoxide; 4-fluoro-3-nitrophenyl 3-nitrophenyl sulfone;
p-fluorophenyl methyl sulfone; p-fluorophenyl phenyl sulfone;
p-fluorophenyl p-tolyl sulfone; (phenylsulfonyl)acetonitrile; methyl
methylsulfinylmethyl sulfide; 4,4'-sulfonyl-bis(methylbenzoate);
4-nitrophenyl sulfone; phenyl trimethylsilylmethyl sulfone;
4-methoxyphenyl methyl sulfone; 4-acetylphenyl methyl sulfone; ethyl
phenacyl sulfone; phenyl phenacyl sulfone; phenyl phenacyl sulfoxide;
methyl p-nitrobenzene sulfonate; cyanomethyl benzene sulfonate; methyl
methanethio sulfonate; bis(4-nitrophenyl) carbonate; diethyl
pyrocarbonate; bis(2-methoxyphenyl) carbonate; lithium trifluoromethane
sulfonate; 4-methoxyphenyl benzene sulfonate; methyl fluorobenzene
sulfonate; and methyl trifluoromethyl sulfonate.
In general, the preferred modifiers are those that contain no additional
functionality in the molecule. In other words, the preferred modifiers are
hydrocarbyl sulfones, hydrocarbyl sulfoxides, hydrocarbyl carbonates,
hydrocarbyl thiocarbonates and hydrocarbyl sulfonates.
The organic sulfone modifiers can be monosulfones or polysulfones such as
disulfones. Preferred hydrocarbyl monosulfone modifiers can be depicted by
the formula:
R.sup.1 --SO.sub.2 --R.sup.2
where R.sup.1 and R.sup.2 are, independently, hydrocarbyl groups bonded to
the sulfur atom, or taken together constitute a single hydrocarbyl group
forming a heterocyclic ring system in which the sulfur atom is
singly-bonded to two different carbon atoms of the ring and is thus the
hetero atom of the ring system. R.sup.1 and R.sup.2 can be, independently,
aliphatic, cycloaliphatic or aromatic, and when aliphatic or
cycloaliphatic, either or both of R.sup.1 and R.sup.2 can be saturated or
olefinically unsaturated. Normally, R.sup.1 and R.sup.2 will each contain
up to about 30 carbon atoms, and more preferably up to about 12 carbon
atoms each.
Examples of compounds in which R.sup.1 and R.sup.2 are separate hydrocarbyl
groups include dialkyl sulfones, dialkenyl sulfones, diaryl sulfones, aryl
alkyl sulfones, diaralkyl sulfones, and aryl alkenyl sulfones, such as
dimethyl sulfone, diethyl sulfone, dipropyl sulfone, dibutyl sulfone,
butyl isopropyl sulfone, divinyl sulfone, diphenyl sulfone, phenyl p-tolyl
sulfone, methyl phenyl sulfone, ethyl phenyl sulfone, methyl p-tolyl
sulfone, dibenzyl sulfone, phenyl vinyl sulfone, and analogous compounds.
Mixtures of such sulfones can be used, if desired.
Sulfone modifiers in which R.sup.1 and R.sup.2 form a heterocyclic ring
system with the sulfur atom are cycloparaffinic sulfones or cycloolefinic
sulfones, such as for example, sulfolane, 3-methylsulfolane,
2,4-dimethylsulfolane, sulfolene, 2,4-dimethyl-3-sulfolene,
dibenzothiophene sulfone, pentamethylene sulfone, and analogous cyclic
compounds. Typically, the cyclic sulfones will contain up to about 24 and
preferably up to about 18 carbon atoms in the molecule.
Sulfones having more than one sulfone functional group per molecule are
exemplified by the disulfones represented by the general formula:
R.sup.3 --SO.sub.2 --R--SO.sub.2 --R.sup.4
where R.sup.3 and R.sup.4 are, independently, hydrocarbyl groups bonded to
the sulfur atom, and R is an alkylene or arylene group bonded to both
sulfur atoms. Typically R.sup.3 and R.sup.4, independently, will contain
up to about 30 carbon atoms each, and more preferably up to about 12
carbon atoms each, and are aliphatic, cycloaliphatic or aromatic groups.
When aliphatic or cycloaliphatic, either or both of R.sup.3 and R.sup.4
can be saturated or olefinically unsaturated. Typically R will be an
alkylene group having up to about 18 carbon atoms (and preferably having
up to about 8 carbon atoms) or an arylene group having 6 to about 18
carbon atoms (and preferably having 6 to about 12 carbon atoms.
Illustrative examples of such compounds include
ethylenebis(phenylsulfone), 1,3-propylenebis(ethylsulfone),
1,4-butylenebis(ethylsulfone), 3,3-bis(ethylsulfonyl)pentane,
1,4-phenylenebis(ethylsulfone), 1,4-phenylenebis(phenylsulfone), and
analogous compounds.
Preferred sulfoxide modifiers used pursuant to this invention can be
depicted by the formula:
R.sup.5 --SO--R.sup.6
where R.sup.5 and R.sup.6 are, independently, hydrocarbyl groups bonded to
the sulfur atom, or taken together constitute a single hydrocarbyl group
forming a heterocyclic ring system including the sulfur atom. When
separate groups R.sup.5 and R.sup.6 can be, independently, aliphatic,
cycloaliphatic or aromatic, and when aliphatic or cycloaliphatic, either
or both of R.sup.5 and R.sup.6 can be saturated or olefinically
unsaturated. Normally, as independent groups R.sup.5 and R.sup.6 will each
contain up to about 30 carbon atoms, and more preferably each will contain
up to about 12 carbon atoms. When R.sup.5 and R.sup.6 are in the form of a
single hydrocarbyl group, the cyclic sulfoxide will typically contain up
to about 24 and preferably up to about 18 carbon atoms in the molecule.
Thus the sulfoxide modifiers include dialkyl sulfoxides, dicycloalkyl
sulfoxides, diaryl sulfoxides, diaralkyl sulfoxides, aryl alkyl
sulfoxides, aryl alkenyl sulfoxides, cycloaliphatic sulfoxides, and
similar compounds of this type. Examples of such sulfoxides include
dimethyl sulfoxide, diethyl sulfoxide, dipropyl sulfoxide, dibutyl
sulfoxide, diallylsulfoxide, diphenyl sulfoxide, di-p-tolyl sulfoxide,
dibenzyl sulfoxide, methyl isopropyl sulfoxide, methyl allyl sulfoxide,
tetramethylene sulfoxide, pentamethylene sulfoxide, and their analogs and
homologs.
Preferred carbonate and thiocarbonate modifiers can be depicted by the
formula:
##STR1##
where Q is an oxygen atom or a sulfur atom, and R.sup.7 and R.sup.8 are,
independently, hydrocarbyl groups bonded to the carbonate or thiocarbonate
moiety, or taken together constitute a single hydrocarbyl group forming a
heterocyclic ring system including the carbonate or thiocarbonate
functional group. R.sup.7 and R.sup.8, when separate groups, can be,
independently, aliphatic, cycloaliphatic or aromatic, and when aliphatic
or cycloaliphatic, either or both of R.sup.7 and R.sup.8 can be saturated
or olefinically unsaturated. Normally, R.sup.7 and R.sup.8 as independent
groups will each contain up to about 30 carbon atoms, and more preferably
will contain up to about 12 carbon atoms each. When in the form of cyclic
ring system, R.sup.7 and R.sup.8 constitute a polymethylene group which
can be unsubstituted or substituted on one or more carbon atoms thereof by
univalent hydrocarbyl groups such as alkyl, cycloalkyl, aryl, and aralkyl
groups of up to about 18 carbon atoms, and more preferably alkyl groups of
from 1 to about 12 carbon atoms. Illustrative examples of the carbonate
and thiocarbonate modifiers include dimethyl carbonate, diethyl carbonate,
dipropyl carbonate, dibutyl carbonate, dipentyl carbonate, ethyl methyl
carbonate, diphenyl carbonate, dibutyl carbonate,
5,5-dimethyl-1,3-dioxan-2-one, dibutyl thiocarbonate, diphenyl
thiocarbonate, tetramethylene thiocarbonate, 2-methyltetramethylene
thiocarbonate, 2,4-dimethyltetramethylene carbonate, and similar
carbonates and thiocarbonates. The carbonates are preferred because of
their greater availability and lower cost.
The hydrocarbyl sulfonates can be aliphatic, cycloaliphatic or aromatic in
character and can be sulfonic acid esters or salts. The sulfonates can
have one, or more than one, sulfonic ester or sulfonic acid salt group in
the molecule. Generally the sulfonates will contain up to about 60 or more
carbon atoms in the molecule. For example, the sulfonates can be derived
from alkylaromatic hydrocarbons formed by alkylating benzene, toluene,
xylene, etc., with long chain alkenes or polyolefins of suitable molecular
weight. The esterifying group can be derived from any suitable alcohol,
thiol, phenol or thiophenol. The salts can be inorganic salts or organic
salts, such as, for example, lithium, sodium, potassium, calcium,
magnesium and barium alkylaryl or alkane sulfonates and pyridinium
alkylaryl or alkane sulfonates. Typical esters of hydrocarbyl sulfonic
acids include methyl methane sulfonate, phenyl methane sulfonate, butyl
ethane sulfonate, methyl 1-decane sulfonate, isopropyl 1-naphthalene
sulfonate, dimethyl 2,6-naphthalene sulfonate, ethyl p-toluene sulfonate,
butyl benzene sulfonate, 2-ethylhexyl 1-tetradecane sulfonate, methyl
4-biphenyl sulfonate, and analogous compounds. Examples of hydrocarbyl
sulfonate salts include lithium octylbenzene sulfonate, sodium 1-decane
sulfonate, potassium 1-dodecane sulfonate, pyridinium p-toluene sulfonate,
tetraethylammonium p-toluene sulfonate, lithium 1-tridecane sulfonate,
calcium octylbenzene sulfonate, and their analogs.
As noted above, olefin functionality may be included in the modifier. In
such cases the modifier may become incorporated into the oligomer, and
this may be desirable when using the oligomer for certain heavy duty
lubrication applications.
One special class of modifiers of this invention is made up of the
oligomeric and polymeric forms of the modifiers. These may be formed by
appropriate known direct or indirect synthesis procedures, and the
oligomers can be formed from one or more than one monomer as long as the
overall product contains the requisite functionality (and optionally and
additionally, the permissible functionality) of the modifiers of this
invention, and does not contain functionality that would impair the
ability of the modifier to perform its intended function. The
functionality can be included in the oligomer or polymer chain, as in the
case, for example, of an oligomeric or polymeric aromatic sulfone.
Alternatively, the functionality can be in dependent side chains of the
oligomer or polymer. Conceivably, the functionality could be in both the
oligomer or polymer chain and in dependent side chains as well. A feature
of such oligomeric or polymeric modifiers is that they may be readily
separated from the oligomerization product mixture, such as by filtration,
or by precipitation and subsequent filtration, centrifugation or
decantation.
Methods for forming such oligomeric or polymeric modifiers are known and
reported in the literature. For example, methods for synthesis of
poly(sulfoxides), poly(sulfones), and appropriate derivatives of
poly(sulfonic acids) such as poly(sulfonates), poly(sulfonic acid salts),
and poly(sulfonyl halides) are referred to in Encyclopedia of Polymer
Science and Technology, Volume 13, Interscience Publishers, copyright
1970, pages 460-470 and in the relevant references cited therein in the
bibliography on pages 472-477, all of which material is incorporated
herein by reference.
While normally a single modifier is used in the process, suitable mixtures
of two or more modifiers can be employed, if desired.
In conducting the process of this invention the alpha-olefin or mixture of
alpha-olefins, boron trifluoride, protic promoter and modifier can be
charged to the reactor in any suitable sequence. Preferably, however, the
modifier should be present before any substantial amount of
oligomerization has occurred. In this way the maximum beneficial reaction
modifying effect of the modifier can be realized.
The reaction can be carried out as a batch, continuous, or semi-continuous
process at temperatures which typically are in the range of 0.degree. to
200.degree. C., and preferably in the range of about 30.degree. to about
150.degree. C. More preferably, the temperature is maintained in the range
of about 20.degree. to about 60.degree. C., and especially in the range of
about 40.degree. to about 60.degree. C. The reaction is typically
conducted at pressures ranging from atmospheric up to, for example, 1000
psig, and preferably in the range of about 5 to about 100 psig. The
progress of the reaction can be monitored, if desired, by taking samples
of the oligomerization mixtures at suitable periods during the course of
the reaction and subjecting the sample to gas chromatographic (GC)
analysis. In this connection, all references in this specification and in
the claims to weight % of oligomer components in the oligomerization
reaction product mixture are based on GC area percentages in which the
analyses are conducted using a Hewlett Packard 5890 gas chromatograph
equipped with a flame ionization detector and a methyl siloxane column
operated under the following conditions: initial temperature=100.degree.
C.; final temperature=350.degree. C.; Rate=15.degree. C./minute.
The reaction can be conducted in a single stirred reactor or in a series of
reactors.
To terminate the oligomerization reaction when the desired product
distribution and olefin conversion have been achieved, the dimer enriched
reaction mixture can be quenched with or in water or an aqueous solution,
such as a solution of a salt or a base, or more preferably a solution of a
strong base such as sodium hydroxide or potassium hydroxide. The organic
phase is recovered and unless the oligomeric product is to be used in the
form produced, the reaction product is distilled to recover the product
fraction(s) desired. Unreacted olefin can be recovered and recycled.
In most cases the modifiers are used in proportions relative to the
promoter that will peak the oligomerization at the dimer stage, but in
some cases the proportions can be adjusted for peaking at the trimer
stage. Thus in general the ratio of modifier to promoter will usually fall
somewhere within the range of from about 0.1 to about 10 moles of modifier
per mole of promoter, and typically within the range of from about 0.5 to
about 2 moles of modifier per mole of promoter. For producing product
containing at least 50 wt. % in dimer, the preferred proportions fall in
the range of from about 0.75 to about 1.25 moles of modifier per mole of
promoter. Where the modifier is difunctional (e.g., when a disulfone is
used) the molar amount of the modifier should be reduced by about
one-half, and further proportionate reductions should be considered for
use when the modifier being used is in the form of an oligomer or polymer.
It should be understood that one should use a suitable ratio for achieving
the particular results desired under the particular reaction conditions
and with the particular materials selected for use. Thus the ratio that
will best serve the needs of the situation at hand can be determined by
performing a few oligomerizations using procedures such as given in the
following illustrative examples.
EXAMPLES
1-Decene, 1-butanol (1.0 mole % based on 1-decene) and the amount of the
modifier (see in Table I), are charged to a reactor equipped with cooling
means, stirring means and inlet/outlet ports. The reactor is sealed and
pressurized (10 psig) with boron trifluoride, and the temperature of the
stirred mixture is maintained at 50.degree. C. by external cooling for the
duration of the reaction. Periodic samples are taken for GC analysis to
monitor the progress of the reaction. To terminate the reaction, the
reactor is vented into a caustic scrubber, purged with nitrogen, and the
reactor contents are drained into 10% aqueous caustic solution. The
product is then washed twice with water. The final product mixture is
analyzed by GC for product composition.
In Table I the modifiers are identified as follows: A is dimethyl
sulfoxide, B is propylene carbonate and C is sulfolane. Control 1 of Table
I was a run carried out in the same manner as the above examples except
that no modifier was used. In Control 2 of Table I the modifier, in this
case, propylene carbonate, was used without the protic promoter, and the
temperature was 45.degree. C.
Table II shows the results of another Example of this invention which was
conducted as in Example 5 except that 1.0 mole % of 1-methoxy-2-propanol
was used as the protic promoter.
TABLE I
__________________________________________________________________________
Modifier
Time,
C.sub.20,
C.sub.30,
C.sub.40,
C.sub.50,
Conversion,
Example
Promoter
(mole %)
min.
% % % % %
__________________________________________________________________________
1 Yes A (1.0)
180 58.3
16.5
2.3
0.3 77.5
2 Yes A (0.5)
150 47.0
24.8
3.0
0.5 75.3
3 Yes A (1.5)
180 37.7
9.7
0.7
-- 48.2
4 Yes B (1.0)
180 67.1
21.6
3.6
0.1 92.4
5 Yes C (1.0)
180 74.3
15.2
1.5
-- 91.0
Control 1
Yes None 120 11.8
65.2
16.7
3.8 97.6
Control 2
No B (1.0)
120 6.2
1.8
-- -- 7.5
__________________________________________________________________________
TABLE II
__________________________________________________________________________
Modifier
Time,
C.sub.20,
C.sub.30,
C.sub.40,
C.sub.50,
Conversion,
Example
Promoter
(mole %)
min.
% % % % %
__________________________________________________________________________
6 Yes C (1.0)
180 80.3
10.9
1.0
0.6 92.8
__________________________________________________________________________
It will be noted from the results of Control 2 that the modifier is not
itself a promoter as no significant oligomerization occurred. Thus the
modifier cooperates with the boron trifluoride catalyst and the protic
promoter to provide the desired peaking or enrichment of the reaction
product at the dimer stage.
The entire disclosure of each and every U.S. patent referred to in any
portion of this specification is incorporated herein by reference for all
purposes.
This invention is susceptible to considerable variation in its practice.
Therefore the foregoing description is not intended to limit, and should
not be construed as limiting, the invention to the particular
exemplifications presented hereinabove. Rather, what is intended to be
covered is as set forth in the ensuing claims and the equivalents thereof
permitted as a matter of law.
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